Directive radio repeating system



May 8, 1928. l1,669,123`

l.. ESPENSCHIED ET AL DIRECTIVE RADIO REPEATING SYSTEM Filed Dec. 28, 1921 3 Sheets-Sheet 1 liz/1m. Jini fn. ik

Le l/ ATTORNEY f, 5 @L L; INVENTORS May 8, 1928. 1,669,123,A

L. ESPENSCHIED ET AL DIRECTIVE RADIO REPEATING SYSTEM Filed Dec. 28, 1921 3 Sheets-Sheet 2 ATTORN EY May 8, 1928. I 1,669,123

L. EsPENscHlED ET AL n DIRECTIVE RADIO REEATING SYSTEM Filled Dec.-28, 1921` 3 Sheets-Sheet 5 ATTORNEY Patented May 8, 1928.

UNITED STATES A CORPORATION OENEW YORK.

,A i I 11,669,123,

v DIRECTIVE Ramo RERE'ATI-NG SYSTEM.

Appiieanon inea December' 2s, 1921. ls'eriaim.` `5,5,443.f

This invention relates to radio repeating.

systems and particularly to systems of the' type employing directive antenna arrays adjusted for unilateral and duolateral recep-k tion and transmission Of signals. Y

j In our '.copending application, Serialv No. 525,442, filed December-28, 1921, there is disclosed means for the directive ,rela-ying of radio signals which are characterized by the'change of frequency at the repeating point so that the transmitted frequency Iis 'different from the received frequency of antenna array for therece-ption and trans-' any given channel, and .further vcharacterized by bilateral reception and transmission By bilateral is meantl equal reception or transmission efficiency in tWo directions diametrically opposite to each other.

It is the object ofthepresent invention to' provide an arrangement for relaying radio signals in which reception is efficient from onedirection only, and likewise, transmis-y sion is. efficient in one direction only` Another 'object of this inventionv is to provide an arrangement for the efficient relaying of radio signals, the angular dierence between the direction of reception and transA mission being less than 180 degrees., g n

lBy the use of repeating stations e1nbo`dyl ing directive antenna arrays and their associated amplifying circuits, the course of transmission of signals betweenwidely sepa: rated terminals may be controlled, since it is practicable, by properly locatingtlierepeatingY stations, to direct the transmission either along a straight line between the .two terminals, or along a more devious course.

This feature of our invention becomes niOreLV important when it is desired to avoid objects lying between the two terminals which would tend toy interfere with .the propagation ofelectro-magnetic waves, or when, for

vtratlic or other reasons, itY would bedesirable to transmit the signals'oyer the more indirect route.

apparent from the following description when read in connectiony with the attached drawings, ofwhich Figure lrepresents'an mission of signals With a single local-circuitshoivnY completely for illustrative ypurposes; Figs. la and lb represent twounilateralcharacteristics Of the array shown in Fig. vl, andFig. lc shows the frequency dis-V tlibution throughout such arep-eati'ng-` :sys-r tem ,i Fig. 2 Vvshows another form; of.4 repeat-y unit of anar-ray .employing a .ground an-y LLOYD EsrENsoEIED, oEQUEENs, NEW YORK/AND DE Loss R: MARTIN, OE ORANGE," a NEW JERSEY, AssIeNoEs To AMERICAN TELEPHONEAND TELEGEAPH comuna-Y,

tenna` forv receiving and a vertical antenna... 1

for transmitting; F 4.-v shows l.an arrangef vinent employing tivoY arrays and four frequencies'to effect simultaneous radiationand reception from VVboth directions, the system having a duolateral characteristic as shown in Fig. 4;?"- and having the frequency diS-` Aiss-,5 and; 5 illustrate ways for .effecting an indirect tribution as-shown in Fig. 4b.; l*

course of transmission betweenl terminals; and Figs. 5b, 5 and 5d show various arrangements of the -antennze andthe individual Y amplifyingcircuits of such arrays.

antennae of an array, each responsive to two,

frequencies f1v andl f2, together with any. side bands offfrequencies that maybe superseparated Vgeog'raphically as shown in the ligure a. :definitefraction Of'a `Wave length apart. The antenna X1 is connected by` means of the triple'windin Vtransformer T,

Ink Fig.l 1, and Xirepreent, three] withy its local ampl'ify'inflr circuit containingl a phase shiftingdevice S1, aband filter Fl adaptedto` transmit kfrequencies flic, av lovs1v power amplifier' A1, a modulator M1 having associated therewith an Voscillator Olpro-l duc'ing unmodulated oscillations Aof the frequencyifa, another band filter F2 adapted to transmit thefrequencies fzis, a power ammitting the saine `frequencies as F2, and -a second Aphase. shifting device PS2. VIt is to,

circuits are connected with the antennae X2,

X3, etc., of the array. Oscillations of the `plifier A2,: a thirdk band filter F3 trans# Y Y p 1 V- frequenciesflis,"which are receivedbyfthe ,f Further objects of this invention Will beV antennajXl, for example, willvbe impressed.

bythe transforme-r T'lrkuponthez local circuit;-

Current atthat frequency lWill, belgiven a b andfilter vvF1v and Will bea-mplified by the amplifier. A1. The amplified current ofthe frequency-fris will be impressed vupon ,thekv modulator Mi, together vWit-h currentrof. the y frequency f, from the local source lThe currents cfg thesefiequencies` will be 'beaten together in the modulator M1 and the resultant currents of the frequencies representedfby the bandl fzis `where may einem, wiiiA beiaiismi'iedl through the'filter F2 and amplified to the requisite degree by the power amplifier Agi The resultant amplified current wilL be tra-ns.-4 mitted through the band filter F3 and given the proper phase adjustment'by'the phase-- shiftingdevice PS2 before impressing it upon thev antenna X1, which asV stated, is adapted y theoretically perfcctg'situation, not signa-ls' of to? respond to the frequencies )Cgi s. Similar action takes' place in the local circuits connectedwith the antennae X21X3, etc., of the array I f By proper spacingV ofthe-antennae of the array and by proper adjustment of the phase of the current in each local circuit by means of the phase shifting devices PS1 and PS2', etc., and by suitable control ofthe amplitude ofthe oscillations by means ofthe amplifiers in the manner clearly set fortlrin the application. of George A. Campbell, Serial No. 327,553, filed September 30, 1919, unilateralk 1 reception and transmission of signals may be effected. w Fig.- la represents the characteristic o'f the lsystem when it receives most efficiently signals at the frequency f1 from the right and transmits signals at the frequency f', along a narrow strip towards the left. In a system having this characteristic, which is a rent inthe local circuit in order to'give the system thev characteristic shownrin Fig) 1b inl whichv reception at the frequency f1 isA eicient from the `left and transmission at the Vfrequency f2 is efficient towards the right. -F ig.. lc shows the distribution of frequency at the various repeaters represented by the numerals l, 2, 3, etc., located. in a system between the terminalstations A and B. Thus,

signals of the frequency f-transmitted-from station A to relay station l', will be changed to the frequency f2 and transmitted tothe relay station 2, wherethey will be changed again to frequency f1 and transmitted to station 3; Here the frequency-willbe stepped up to f; and transmitted to station 4 where the frequency will' be' stepped down again .to

f1 and transmit-feeli tothe terminal station Bi' Transmission in thefoppositedirection from station B to station A atoriginatingfre- V- quency f is indicated bythe light: solidline.

vFig 2,!sho`ws an arrangement'employing two arrays, one for receiving, the other for transmitting, whereby simultaneous Htwo-way voperation of the systemiseile :te 1 iI In this figure X1, X, and X1 represent three receiving antennae, each responsive to the freis shown1connectedA withl two. circuits, the upper one containing the phase shifting device PS'1,'aba11d filter F1 transmit-tino frequencies his, and a detector D1. The ower branch -lcircuit contains similar apparatus but the filter F is adapted -to transmit frequencies his. These branch circuits are connected to vtransmission conductors L1'and L2, which areg'common to the respective up-4 per and lower branch circuits of each of' the Vother antennaeofthe system X,`X3, etc;

The transmission conductors L1 and L2v are connected respectively with the lower andupper branch circuits connected withy the antenna of the transmitting array, of which X1 is an example. The lower branch cir! cuit .of the transmitting antennal XL con--l tains an oscillator O1 generating a frequency Vfalencias f1 and f2, fand-i ther respecte@ ad@ bands 1*; The antenna X1v for enaniple,

f, a modulator M1 for modulating frequencyf2 with the band frequencies 9, a filter adapted to transmit .frequency f2s-rs, ,which is the resultant frequency range of* the modulator M1,`and a phase shifting device PS3 designed to control the phase oftheY current supplied by this branch circuit tothe.

transmitting antenna X1.v Similarapparatus is connected with thek upper branch circuit of the transmitting antenna, excepting that the band filter F4 is designed' totransmit' frequency f1 i s, which is the resultant range of frequencies of the modulation of` the band s from line L2, with the loscillations of the frequency f1 from the oscillator O2.

oscillations of' the frequency f1 is' set up in the receiving antenna X1 bythe waves of that frequency will be transmitted through theu'pper branch circuit, beinggiven a suitable phase yangle by the phase shifting devices`PS1. These frequencies willbedetected by the detector D1 and the resultant low' frequency oscillations will bev transmitted over the line L1 yto the modulatoi- M1l connectedwith the output branch of the sysfl tem. Here they will be beaten with the oscillations of the frequency f2 and converted to a high 'frequency band represented' by i f2 is.4 These oscillations willbe transmitted through the filter Fsiandiafter being given the proper phase angle bythe phaseshifting devicePSsto in sureproper directivity ofv the array` they will be transmittedfrom the antenna `X'1. `The characteristicshown in Fig. 2 shows that the system can beinade effectiveV for simultaneous `twoway operation lby the proper adjustment of the phase shifting devices. Thus, in Figg'2, the lower p'air lofv loops represents two unilateral 'char a'cteristics of the receiving antenna and the` upper pair of'loops'mrepresents twofunilatf eralcharacteristics ofthe transmitting antenna Thus, by the proper Aad'justir'iei'it of the phase shifting device PS1 andr similar devices in the similar branch circuitsfconnected with the other `receiving antennaeXz.,

X3, etc., of the array, oscillations of the fre-'l quency F1, (together with its side bands is), will bel efficientlyv received from the right. These oscillations aredetectedv and the side band frequencies s Vtransmitted over shown in the upper characteristic :of Fig. 2.

the lineL to 'thetransmitting branchlof the system, where vthey will, modulate the. fre-h diated in a 'narrow band toward they left, as

The system can beimade rresponsive to oscillations of the frequency f2 receivedV from:

the leftby the proper adjustmentv of the phase shifting device PS2 (and similar part-s of the other receiving antenna) and it can be adjusted to transmit!oscillations of .the frej queiicy f1 toward the right,-.as shown in the upper characteristic of Fig. 2a by suitable adjustment of the phase shifting device PS4 (andsimilar parts of the other transmitting antenna). Y 1

Fig. 3 shows employing two arrays, one consisting of ground antennae forreceiving and thoother consisting of vertical antennae for transmit--` ting. A repeating station made up of units i as shown in Fig.- 3 may be adapted forl simultaneous Y two-way relaying of signals. Directivity of reception'can be obtained by the proper adjustment ofthe phase shifting:

devices PS1k and PS2 and similar phase controlling devices on the other circuits .of the antenna array. lIn like-manner directivity and PS4 and'siniilar devices in similar circuits of the array. Thus, for example, the phase shifting device PSl andl the y.correspoiidingly located phase shifting devices of allithe other local circuits connected with kthe other receiving antennae of the system along a narrow strip from the right. TheV phase shifting device PS3 and its .correspending associates in the other circuits would be adjusted to give .directivity of transmission along a nairow bandtowardthe right and the phase shifting device PS4 -and its corresponding associates would be adjusted to give'directivity of transmission of the frequency f1 toward the left. The oscillator O1 is'designed to generate a frequency which, when beaten with the freal 'unit of a repeating station" quency f1, will produce f2, i and inl like man# nerwhenbeaten with the frequencyV f2 will" These output frequencieswill' be selected by the suitable band -filters P3, j

produce 76,.

and F4 and when given the proper phase angle by the-phase shifting devices PSavand':

PSet will be radiated from the antenna'Xl.

The characteristic of j such a system; is 'that 'shown in Fig. 2". 'f i Y i Fig. 4 shows,as stated, an arrangement: for duolateral transmission and receptionl j of signals. VThe receiving antenna llisfre-fv j. -sponsive tothe frequencies f1 andi.;v andthe transmitting antenna tothe frequencies y.

and Itis to b e understood that a band offrequencies'such as flits, etc.,'can bere.-y ceived. and transmitted fiointheserantennae;

The received' frequencies would passfinto .their .respectivebranch circuits which are.`

coupled with the receiving antennae,` `depending upon the transmission characteristicsaofi the filters F1 and F2. Thephase angle of-the.

received current lof-each frequency :in each local circuit of a Arepeating station wouldlbe controlled by the phase shiftingdevices PS1 and PS2.rv The currents .would beamp'lified by the ampliierA1 and modulated in thc- Imodulator M.L with. current of-the frequency:

f5 obtained fromthe source O1. The fre-L Y quencies selected as a result of modulating .the frequency f3 with f5 is the frequency f2 and in ylike manner the'frequency selected as a result of'modulating fi with 'f5 is"'thefre-Y quency f3. qu'enciesl Wouldbe amplified by the :power -ampliier A2 andtransmitted intof their ape Currents ofy these resultant frez- Y ion' propriate' branch circuits, depending upon the transmission;characteristics of the filters`r` F3. and F4'. The resultant currents would be given in each local circuit the proper?- of transmission can be effected by the proper adjustmentof the phase shifting devices PS3 phasing by means of. thephase shifting devicesfPiSl.,` and PS4, and transmitted from the;v

antenna X1. Fig. 4a. shows the character-is!v tics of a system which is adjusted to` receivev Simultaneously from'ft-Wo ydirections which are separated by the angular distance a and 'n lig. 4b represents v`the frequency distribution in a duolateral system--havingtwo krepeate ing stations l and 2 interposed betweenthe terminal stations Aand B. l Thus,station 1` `is intended to receive frequencies f, and f,

and to transmit frequencies j f and f3', that simultaneously from two directions separated'by the angular distance a and also the frequency fpwould be received from` the In like manner, fre-l same two directions. qiiency f24 would be transmitted simultane- `12e Y is to say, the frequency f1 would-be received Y.

ously in two directions separated by the an- Y l gular distance@ and also thefrequency f3 would be transmitted in thevsame way.

The application ofeither the'unilateral rays;

or the dlateral system s clearly showiiin Figs. 5 and 51 wherein it s desred'to relay the received-signals, giving the transmitted waves diiferentdrection from the re.- ceived waves; Thus, in Fig.y 5, A and B represent two terminal stations having a relay station l `located between thexngr At ystation l, tliedifference instlirection yof the received and transmitted waves A is represented by the angle a'. F ig; 5: sliowsthel use at therepeating station l of two array-s eac-li designed to have a unilateral characteristic,

oneffbr receiving and the other for transmittingthe signals. `In Fig. 5, a single array is Lusedv which visdesigned to have avduo-v Fig. 5d represents an arrangementnwhicli the antennae of the receiving array are along the sainefaxisas anten'nte ofthe transmitting array. The adjacen'tantennee of the receivingY array are spacedat a definite fractional Wave length apart in` a mannenl similar to that in whichv the antennae ofi' the transmitting array are spaced.y The'corresponding pairs oft-ransmitting and receiving antennae` arev joined bythe local circuits, as; shown, designated A.

It will be seen thatA by means ofithe fore!- goingarrangeinent's', signalsiiiay be received efficiently from any one direction and trans-v initted etiiciently in anyv other direction without producingundesirable reaction at the repeating station; eral type, signals may be received efficiently from two direction-s less than 18() degrees apartl and transmitted in two directions alsoless than 180 kdegrees apart, without producing undesirable reaction` at' the station'.

Although this invention has been dis- Also by the duolatf repeating temi-s closedcas embodied in specific ferinsand are rangements of parts, it isv to be understood w that it iscapabl'e'of embodiment in other and different for-ins without departingffionir the spirit and scope of the appended claims;-

4Whatis claimed is; l

l. In a radio repeating system characteriedby directive control of received and transmitted waves, the combination with .af receiving antenna array timed to a definite frequency of av transmitting ant-enna. array balanced witlrrespect ,tofthereceiving antenna array and! timedA to different frequency,'and a pluralityv of amplifying cir-V cuits individual t'o and `connected with apair of antennze" one from cach airay,rliav-" ing.r frequency changing means, amplifying.'

means connected" therewith, andI means` connected with eaclr ofl said other means to ad'- just the vphase of the received and .trans--y initted currents to produce unilateral: recepition and; radiation'.

2. In v`a radio: repeating system characterized by directive control ofV received and` transmitted wave-s, the combination ,with arece'iving antenna array tuned to afdeinit'c frequency of. a transmitting antenna array tuned to a different frequency, means to reduce the' frequency off-.the received waves, means to amplify the said iva-vest means to increase-'the frequency of the said waves before .radi-ation,- and means. to adjust the phase of the "currents resulting.V from said wavesfor unilateral receptionand transmission. c Y

3'. Ina radiofsy'stem 'characterized byV directive `control. of received and transmitted waves, the. combinationfwith a receiving antenna array tuned to adeinite frequency offa.transmitting-antenna array tuned to a different frequency, 'means-to reduce the fre'- q uen'cyof the receivedwaves, meansto amplify thesaidjwaves, means to increase the frequency of the said wavesl before radiation,-and means to adjust the phase of.. the

currents resulting fromsaid Waves, to control the direction of reception and transmission. y

In testimony. whereof` we have 'signed our names to this' specification this 27th (la-y of December, 1921. Y, Y c i LLOYD ESPENSCHIED.

DE 'LOSS-K; MARTI-N.-V 

